Synthesis and Acid Hydrolysis of Monophosphate and Pyrophosphate Esters of Phytanol and Phytol

1973 ◽  
Vol 51 (11) ◽  
pp. 1527-1536 ◽  
Author(s):  
C. N. Joo ◽  
C. E. Park ◽  
J. K. G. Kramer ◽  
M. Kates
Keyword(s):  
Acid Hydrolysis ◽  
Infrared Spectra ◽  
Dipotassium Salt ◽  
Hydrolysis Products ◽  
Elementary Analysis ◽  
Catalytic Hydrogenolysis ◽  
And Behavior ◽  
Hydrolysis Of

Monophytanyl phosphate was synthesized by phosphorylation of phytanol with diphenylphosphoryl monochloride followed by catalytic hydrogenolysis of the phenyl groups; the product was isolated as the dipotassium salt. The phytanyl pyrophosphate was prepared by phosphorylation of phytanol with monophenylphosphoryl dichloride followed by aminolysis and saponification of the resulting phytanylmonophenylphosphoryl monochloride to the phytanyl phosphoramidate. The latter, as the cyclohexylamine salt, was reacted with dioxane diphosphate in the presence of pyridine to give the desired phytanyl pyrophosphate isolated as the tripotassium salt. Alternatively, the phytanyl pyrophosphate was made from phytanyl monophosphate via the phosphomorpholidate. The 2-phytenyl (phytyl) pyrophosphate was synthesized more directly by phosphorylation of phytol with di-(triethylammonium) phosphate in the presence of trichloroacetonitrile in acetonitrile as solvent. The phytyl pyrophosphate and the accompanying phytyl monophosphate were isolated as tri- and diammonium salts, respectively. These mono- and pyrophosphates were characterized by elementary analysis, infrared spectra, and behavior towards acid hydrolysis; the hydrolysis products formed are characteristic of the phytyl or phytanyl phosphate hydrolyzed and may be used for their identification.

On the synthesis of 3,4-dihydroxyprolines. II. Synthesis, stereochemistry and reactivity of some 3,4-Epoxy-DL-proline derivatives

1975 ◽  
Vol 28 (11) ◽  
pp. 2479 ◽  
Author(s):  
CB Hudson ◽  
AV Robertson ◽  
WRJ Simpson
Keyword(s):  
Acid Hydrolysis ◽  
Methyl Esters ◽  
High Yield ◽  
Butyl Esters ◽  
Epoxy Acids ◽  
Trifluoroperacetic Acid ◽  
Catalytic Hydrogenolysis ◽  
Direct Separation ◽  
Proline Derivatives ◽  
Hydrolysis Of

N-Protected esters of 3,4-dehydro-DL-proline react with trifluoroperacetic acid to give, in high yield, approximately equal amounts of the corresponding stereoisomeric 3,4-epoxy-DL-proline derivatives, direct separation of which proved difficult. However individual members of the two families were obtained by discovery of selective transformations and fractionations. Relative configurations of the two 3,4-epoxy-N-tosylproline methyl esters were established by borohydride reduction to authentic 4-hydroxy-N-tosylprolinols. Epoxide reduction is regioselective. Extensive p.m.r. analyses then permitted stereochemical assignment of other derivatives. These epoxides are remarkably resistant to catalytic hydrogenolysis, and to hydration in acid or alkali. N-Substituted 3,4-epoxyproline methyl esters undergo ready β-elimination in alkali to yield the corresponding 4-hydroxy-2,3- dehydroproline esters and ultimately the N-substituted pyrrole-2- carboxylic acid or ester. Prolonged aqueous acid hydrolysis of 3,4- epoxy-N-tosylprolines, or of their methyl esters, gives mixtures of 3,4-dihydroxy-N-tosyl-DL-prolines in the 2,3-cis-3,4-trans and 2,3- trans-3,4-trans families. Their stereochemistry was allotted from p.m.r. of the diacetate methyl esters. During acid hydrolysis of 3,4- epoxy-N-tosylproline methyl esters, the ester of the trans stereoisomer hydrolyses selectively, and some epimerization of the cis stereoisomer occurs. Ester hydrolysis is much faster than epoxide hydration. Anhydrous acid cleavage of 3,4-epoxy-N-tosyl-DL-proline t-butyl esters to the epoxy acids is unusually slow.

scholarly journals HPTLC determination of diosgenin in fenugreek seeds

2018 ◽  
Vol 68 (1) ◽  
pp. 97-107 ◽  
Author(s):  
Barbara Król-Kogus ◽  
Khenifi Mohammed Lamine ◽  
Piotr Migas ◽  
Messaoud Boudjeniba ◽  
Mirosława Krauze-Baranowska
Keyword(s):  
Ethyl Acetate ◽  
Acid Hydrolysis ◽  
Methanolic Extract ◽  
Soxhlet Extraction ◽  
African Origin ◽  
Fenugreek Seeds ◽  
Hydrolysis Products ◽  
Hydrolysis Of

Abstract A new HPTLC-densitometric method for diosgenin determination in fenugreek seeds was established after optimization of the conditions for efficient saponin extraction and acid hydrolysis. Several procedures were tested, the best of which was a three-step Soxhlet extraction, followed by hydrolysis of the obtained methanolic extract with 2 mol L-1 H2SO4. Best diosgenin separation from other hydrolysis products was obtained on HPTLC Si60F254 plates u sing a mixture of n-heptane/ethyl acetate (7:3, V/V) and modified anisaldehyde as a spraying reagent. The method was preliminarily validated and the determined amounts of diosgenin in fenugreek seeds of Polish and African origin were found to be similar and ranged from 0.12-0.18 %.

N-Unsubstituted 1,2,4-Triazole-3-carbaldehydes

1971 ◽  
Vol 24 (2) ◽  
pp. 393 ◽  
Author(s):  
EJ Browne
Keyword(s):  
Solid State ◽  
Acid Hydrolysis ◽  
Infrared Spectra ◽  
Mass Spectra ◽  
Essentially Normal ◽  
Hydrolysis Of

A series of N-unsubstituted 1,2,4-triazole-3-carbaldehydes has been prepared by acid hydrolysis of their methyl or ethyl acetals. Those with 5-aryl substituents have been shown to dimerize in the solid state to carbonyl-free hemiaminals. P.m.r. and infrared spectra indicate that monomeric 1,2,4-triazole-3-carbaldehydes are present in solution, the dimers being reformed on removal of the solvents. Parallels are drawn with benzimidazole-2-carbaldehyde, to which a similar structure has been assigned. With non-aromatic 5-substituents the hemiaminal becomes less stable, and 1,2,4-triazole-3-carbaldehyde, itself, exists predominantly in the carbonyl form. Mass spectra were consistent with essentially normal aldehyde structures.

THE PRESENCE OF MONOTHIOCARBONATE SUBSTITUENTS IN CELLULOSE XANTHATES

1960 ◽  
Vol 38 (8) ◽  
pp. 1381-1394 ◽  
Author(s):  
D. A. Andrews ◽  
F. G. Hurtubise ◽  
H. Krässig
Keyword(s):  
Acid Hydrolysis ◽  
Infrared Spectra ◽  
Cellulose Xanthate ◽  
Ultraviolet Spectroscopy ◽  
Hydrolysis Of Cellulose ◽  
Comparison Of The Results ◽  
Hydrolysis Of

The presence of monothiocarbonate substituents in viscose has been demonstrated by the infrared spectra of the gases evolved during the acid hydrolysis of cellulose xanthate salts and viscose. A comparison of the results of various methods of sulphur determination and the results obtained by ultraviolet spectroscopy has been made. The results of investigations on sodium cellulose monothiocarbonate preparations support the concept of monothiocarbonate substitution.

DETERMINATION OF MICRO-AMOUNTS OF 5β-PREGNAN-3α-OL-20-ONE IN URINE USING INFRARED-SPECTROMETRY

1962 ◽  
Vol 41 (2) ◽  
pp. 234-246 ◽  
Author(s):  
H. J. van der Molen
Keyword(s):  
Infrared Spectrum ◽  
Quantitative Determination ◽  
Acid Hydrolysis ◽  
Chromatographic Separation ◽  
Pure Form ◽  
Infrared Spectrometry ◽  
Hydrolysis Of

ABSTRACT A procedure for the quantitative determination of 5β-pregnan-3α-ol-20-one in urine is described. After acid hydrolysis of the pregnanolone-conjugates in urine, the free steroids are extracted with toluene. Pregnanolone is isolated in a pure form as its acetate; after chromatographic separation of the free steroids on alumina, the fraction containing pregnanolone is acetylated and rechromatographed on alumina. Quantitative determination of the isolated pregnanolone-acetate is carried out with the aid of the infrared spectrum recorded by a micro KBr-wafermethod. The reliability of the method under various conditions is discussed under the headings, specificity, accuracy, precision and sensitivity. It is possible to determine 30–40 μg pregnanolone in a 24-hours urine portion with a precision of 25%.

Optimization of technological modes of cold acid hydrolysis of potato starch

2020 ◽  
Vol 26 (3) ◽  
pp. 222-233
Author(s):  
M. Alekseenko ◽  
V. Litvyak ◽  
A. Sysa ◽  
E. Hrabovska ◽  
O. Galenko
Keyword(s):  
Acid Hydrolysis ◽  
Potato Starch ◽  
Hydrolysis Of

FLOWTHROUGH ACID HYDROLYSIS OF RAPESEED STALKS

2012 ◽  
Vol 11 (12) ◽  
pp. 2313-2318
Author(s):  
Theodor Malutan ◽  
Adina Elena Panzariu
Keyword(s):  
Acid Hydrolysis ◽  
Hydrolysis Of
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